I had to think carefully if I would ever agree with 'plausible situation' at any point of my career. And the answer is no. If they really needed 2-3 ppl they would have adjusted their sponsorships/donations plan and picked up those ppl full time. There are costs of bigger teams and wider contributor networks that are rarely advertised.

But ofc what can I know about browsers, I am just a gamedev. From my PoV (studio tech director) in custom game engines juniors mostly do acts of wanton destruction in the name of curiosity. And then leave for better compensated industries anyway.

In my opinion folks inciting random contributions from webdev crowd unfamiliar with C++ are not helping. And those who are familiar should know better than to do random drive-by features.